Agriculture Reference
In-Depth Information
6. Future Challenges. There has been a continuous reduction in the
area planted with upland rice in Brazil, because of the widespread
adoption of the soybean crop, even in conditions and regions previously
considered inappropriate for that commodity. Making rice attractive
again to upland farmers in Brazil will require not only high-yielding
cultivars and excellent grain quality but also higher drought stress
tolerance and better adaptation to no-tillage systems. Those two changes
point to the root system as a promising focus of the breeding program.
Rice plants with a more aggressive, deep, and thick root system will be
necessary to thrive in soils with a moderate degree of compaction and to
tap water from deeper soil layers during drought periods within the wet
season, the so-called veranicos .
Although basic research on root-related genes was conducted (Rabello
et al. 2008) and
field evaluation of drought tolerance is now routine with
advanced inbred lines, no direct selection for better root systems has
been made in the Brazilian rice breeding program to date. Furthermore,
unfavorable genetic correlations may have resulted in indirect selection
in an undesirable direction. Selection for shorter, lodging-resistant
plants probably resulted in shallower root systems as well. Field eval-
uations indicate that some Brazilian landraces have higher drought
tolerance than modern cultivars (Heinemann et al. 2011).
The Brazilian rice breeding program will continue to apply the
recurrent selection approach to improve yield, grain quality, and disease
resistance, with a focus on a new target environment, characterized by
the no-tillage system and erratic drought events.
D. Rice Breeding in Uruguay
1. Rice Production in Uruguay. Uruguay, located between 30 and 35
S,
°
has
180,000 ha of long-grain rice crop area, with a production of
1.8 million tonnes, in rotation with grazing pastures, which are mainly
for beef cattle. In the eastern region, wheremost of the rice is cultivated,
the growing crop season is short, lasting from October to April, with
average minimum and maximum temperatures for this period being
13.9 and 26.2
C, respectively. About 95% of the rice produced is
exported and the rice value chain is highly integrated. The Rice
Growers Association (ACA) and Rice Millers Association (GMA) nego-
tiate the rice price each year under a framework agreement, based on
export prices, without government intervention. Without any subsi-
dies, the competitiveness of the rice sector relies on technology adop-
tion, high grain yield and quality, and variety identity for all exported
rice (Blanco et al. 2010).
°
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